Animal migration is the seasonal or yearly movement of birds, mammals, fish, insects and other species due to environmental conditions. It can take many different forms. Altitudinal migration is the movement between higher and lower elevations. Animals that breed high in the mountains will seek lower elevations due to food availbility during the colder months. Intergenerational migration refers to species that complete migration through multiple generations within its lifecycle, as with the monarch butterfly. The longest migration path is completed by seabirds with the Arctic Tern leading the distance league with a 44,000 mile round trip between its arctic summer and antartic winter homes.
We discussed springtime migration in our mid-May blog. This week we feature a small subset of animals with a focus on autumn migration, including insects, mammals and of course a few birds as well.
Elk, also called wapiti, are among the largest ungulates in the United States. Elk migration is altitudinal and, during autumn, those living in the west at higher altitudes will travel dozens of miles to gather in large herds. These large herbivores seek open pastures where they will browse small shrubs or dig through snow to expose suitable grass for grazing.
Most Elk are found in mountainous regions of the western US, including Colorado and Wyoming. There is a population of Tule Elk in California and, in the eastern US, a growing population in Pennsylvania. Once extirpated (locally extinct) due to over-hunting, Elk disappeared from the east in the late 19th century. In the early 1900s a small group of Rocky Mountain and Yellowstone elk were introduced into the state and the free-roaming population now numbers nearly 1000 animals.
Photographer Daniel Dunn and his wife Betty Dunn have spent a great deal of time photographing the PA elk. In Betty's image, this large bull is bugling to establish dominance and attract a mate during the rutting, mating, season. Dan's image features a mature bull alongside a cow and calf.
You can see more of Dan's Elk images featured in this video produced by Lang Elliott and accompanied by audio captured by Mr. Elliott. Visit the Benezette Elk viewing guide for more information about where to view the PA elk. For livestream viewing, visit the PA Game Commision Elk-cam.
2. Green Heron
Ubiquitous wetland birds, Green Herons can commonly be found at both Brick Pond and Apalachin Marsh throughout the summertime. Nesting in trees in rookeries with other herons, the fledgings begin to appear during mid-summer. Less skittish than adults, young Green Herons, like this one photographed by Gina Vaughan, are much more approachable, providing great opportunities for viewing during August and September. Green herons become scarce in late September and by mid-October they will have all begun their journey to the southernmost US states, the Caribbean and Central America.
4. Eastern Kingbird
Eastern Kingbirds are large flycatchers that typically perched in trees, shrubs or on posts searching for insects to catch mid-flight. During autumn migration and throughout the winter they begin eating more fruits and berries. Long distance travelers, these strong birds will flock up to fly as far as South America, commonly the Amazon. Throughout the winter they remain in large groups living in tropical forests along the edges of lakes and rivers.
4. Ruby-throated Hummingbird
In central NY and northern PA during early September we see a flurry of activity on our hummingbird feeders as Ruby-throated hummingbirds begin their migration south. Spending their winter in the very southern tip of the US and Central America, these small nectar-eaters will begin fueling up for the long journey south during the late summer months. Especially during this time it is important to ensure your feeders are clean and filled with fresh nectar.
Kelly Frederick Sweet photographed this female in September 2017. Kelly wrote: "During the fall migration, I've noticed that the Hummingbirds become more aggressive at the feeders. In September of last year this female would stay near the feeder all day eating and guarding. Here she is watching a male that is trying to sneak in for a sip."
5. Ladybird Beetle (Ladybug)
Have you ever wondered how Ladybugs survive the winter? In most regions, Ladybugs seek out south-facing cracks and crevices in tree bark or roofing where they can huddle in large groups for protection from the cold. In colder climates they become dormant in a state known as diapause. Many living in the southwestern US will migrate tens of miles to overwinter in lower altitudes with more temperate climates. Groups of hundreds, even thousands will form aggregates on trees and south-facing buildings where they will spend the winter months.
Ladybugs, as in this image photographed by Cheryl Utter, are not bugs at all. These small insects are omniverous and their diet consists primiarly of even smaller insects and larvae. Although often admired for their bright red color, gardeners and farmers love them as well for their appetite for aphids. Aphids are sap-sucking insects that can infest and damage or destroy plants. A single ladybug can consume as many as 5000 of these tiny pests in its one-year lifespan.
6. Resource Links
Elk River - documentary capturing the migration of Yellowstone Elk
Elks seek open pastures where they can dig through snow to expose grass for feeding
7. About the Author
An active member of the Waterman Center board of directors, Teri Franzen is a professional wildlife photographer, videographer, naturalist and conservationist working to promote natural history awareness through photography education. With a strong emphasis on ethics, Teri is passionate about observing and photographing wildlife on its terms, wild, unaltered and undisturbed.